37 research outputs found
Link Quality Based Power Efficient Routing Protocol (LQ-PERP)
Recent years have witnessed a growing interest in deploying infrastructure-less, self configurable, distributed networks such as Mobile AdHoc Networks (MANET) and Wireless Sensor Networks (WSN) for applications like emergency management and physical variables monitoring respectively. However, nodes in these networks are susceptible to high failure rate due to battery depletion, environmental changes and malicious destruction. Since each node operates with limited sources of power, energy efficiency is an important metric to be considered for designing communication
schemes for MANET and WSN. Energy consumed by nodes in MANET or WSN can be reduced by optimizing the
internode transmission power which is uniform even with dynamic routing protocols like AODV. However, the
transmission power required for internode communication depends on the wireless link quality which inturn depends on various factors like received signal power, propagation path loss, fading, multi-user interference and topological changes. In this paper, link quality based power efficient routing protocol (LQ-PERP) is proposed which saves the battery power of nodes by optimizing the power during data transmission. The performance of the proposed algorithm is evaluated using
QualNet network simulator by considering metrics like total energy consumed in nodes, throughput, packet delivery ratio, end-to-end delay and jitter
Broadcasting with an Energy Harvesting Rechargeable Transmitter
In this paper, we investigate the transmission completion time minimization
problem in a two-user additive white Gaussian noise (AWGN) broadcast channel,
where the transmitter is able to harvest energy from the nature, using a
rechargeable battery. The harvested energy is modeled to arrive at the
transmitter randomly during the course of transmissions. The transmitter has a
fixed number of packets to be delivered to each receiver. Our goal is to
minimize the time by which all of the packets for both users are delivered to
their respective destinations. To this end, we optimize the transmit powers and
transmission rates intended for both users. We first analyze the structural
properties of the optimal transmission policy. We prove that the optimal total
transmit power has the same structure as the optimal single-user transmit
power. We also prove that there exists a cut-off power level for the stronger
user. If the optimal total transmit power is lower than this cut-off level, all
transmit power is allocated to the stronger user, and when the optimal total
transmit power is larger than this cut-off level, all transmit power above this
level is allocated to the weaker user. Based on these structural properties of
the optimal policy, we propose an algorithm that yields the globally optimal
off-line scheduling policy. Our algorithm is based on the idea of reducing the
two-user broadcast channel problem into a single-user problem as much as
possible.Comment: Submitted to IEEE Transactions on Wireless Communications, October
201
Energy-Efficient Transmission Schedule for Delay-Limited Bursty Data Arrivals under Non-Ideal Circuit Power Consumption
This paper develops a novel approach to obtaining energy-efficient
transmission schedules for delay-limited bursty data arrivals under non-ideal
circuit power consumption. Assuming a-prior knowledge of packet arrivals,
deadlines and channel realizations, we show that the problem can be formulated
as a convex program. For both time-invariant and time-varying fading channels,
it is revealed that the optimal transmission between any two consecutive
channel or data state changing instants, termed epoch, can only take one of the
three strategies: (i) no transmission, (ii) transmission with an
energy-efficiency (EE) maximizing rate over part of the epoch, or (iii)
transmission with a rate greater than the EE-maximizing rate over the whole
epoch. Based on this specific structure, efficient algorithms are then
developed to find the optimal policies that minimize the total energy
consumption with a low computational complexity. The proposed approach can
provide the optimal benchmarks for practical schemes designed for transmissions
of delay-limited data arrivals, and can be employed to develop efficient online
scheduling schemes which require only causal knowledge of data arrivals and
deadline requirements.Comment: 30 pages, 7 figure
On the Optimum Energy Efficiency for Flat-fading Channels with Rate-dependent Circuit Power
This paper investigates the optimum energy efficiency (EE) and the
corresponding spectral efficiency (SE) for a communication link operating over
a flat-fading channel. The EE is evaluated by the total energy consumption for
transmitting per message bit. Three channel cases are considered, namely static
channel with channel state information available at transmitter (CSIT),
fast-varying (FV) channel with channel distribution information available at
transmitter (CDIT), and FV channel with CSIT. A general circuit power model is
considered. For all the three channel cases, the tradeoff between the EE and SE
is studied. It is shown that the EE improves strictly as the SE increases from
0 to the optimum SE, and then strictly degrades as the SE increases beyond the
optimum SE. The impact of {\kappa}, {\rho} and other system parameters on the
optimum EE and corresponding SE is investigated to obtain insight.Some of the
important and interesting results for all the channel cases include: (1) when
{\kappa} increases the SE corresponding to the optimum EE should keep unchanged
if {\phi}(R) = R, but reduced if {\phi}(R) is strictly convex of R; (2) when
the rate-independent circuit power {\rho} increases, the SE corresponding to
the optimum EE has to be increased. A polynomial-complexity algorithm is
developed with the bisection method to find the optimum SE. The insight is
corroborated and the optimum EE for the three cases are compared by simulation
results.Comment: 12 pages, 7 figures, to appear in IEEE Transactions on Communication
TESTBED IMPLEMENTATION OF ENERGY EFFICIENT MULTI ANTENNA SYSTEM AND ITS PERFORMANCE EVALUATION
With the recent development and requirement for high-speed wireless communications, the demand of energy has increased exponentially in order to support required quality of service (QoS). Multiple Input Multiple Output (MIMO) technique gaining more popularity in current communication network, since it provides advantages in terms of higher data rates and maximum capacity with the cost of more energy consumption. In this paper, QAM modulation scheme is analyzed as the best modulation scheme for the total energy required to transmit the given number of bits is reduced. A SDR testbed has been built to implement Almouti coded MIMO system using LABVIEW and Universal Software Radio Peripheral (USRP) platform. The analysis was then extended to evaluate the energy consumption of the system where it was observed that by minimizing the transmission power the energy requirement of the system gets reduced. Then the system efficiency in terms of transmit power was evaluated using USRP. It has been observed that by adjusting carrier frequency transmit power of the system gets reduced up to 25%.Finally the performance of the system is evaluated by demonstrating the effect of transmission distance, symbol rate, spectral efficiency and circuit power on energy consumption of the system using LABVIEW math script